Various techniques have been used for embellishing fabrics or other materials with precious metals and other types of metal. According to a sewing or couching technique, precious metal wires and platelets are sewn to cloth and animal skins. One disadvantage to this method is that the thread often breaks and pieces of precious metal fall off the substrate. Also, the metal edges can cut thread and tear cloth.
According to a weaving and embroidery technique, precious metal leaves are glued to both sides of paper sheets using plant and animal derived glues. The sheets are then cut into narrow strips and are woven into cloth. Alternatively, the metal-coated paper strips are wound around thread filament cores and woven into cloth. One disadvantage of this technique is that the paper becomes brittle and tears easily.
According to another technique, metal leaves and powders are glued directly to substrates, such as textiles, wood, metal, glass, and plastics. Traditionally, several different kinds of glue have been used to attach metal to substrates, and the strongest glue bond was made with animal derived, or egg white, glues. However, these adhesives are not lasting, attract bugs and molds, affect the coloration of the metal, and present problems of flaking and cracking. Moreover, there has been an incompatibility problem between the smooth metals and the textural qualities of cloth, which results in “tenting” and causes the metal surface to break. Other types of adhesive used to glue metal leaves directly to substrates include starch pastes comprised of wheat, rice or arrowroot flowers. These adhesives also attract bugs and present archiving problems. Lacquers have also been used for gilding wood and metal surfaces. All of these adhesives present compatibility problems between hard metals and flexible fibers. Because most of these adhesives are water-soluble and form a weak bond, the metal-coated product is not washable.
According to another technique, substrates can be painted with metal powder. Metal dust is mixed into an adhesive base and used to paint the substrate. Using this method on cloth, however, stiffens the affected areas and results in flaking and cracking.
Thus, the existing techniques discussed above all have similar drawbacks. These techniques typically require complicated multi-step processes. The metal-coated products produced using these techniques are also not durable and not washable. Furthermore, these techniques often cannot produce metal-coated products with the high resolution patterning and other aesthetic properties desired in the fashion, interior decorating, electronics, jewelry, and technology industries.
Accordingly, there is a need for a relatively simple method of coating a substrate with a metal layer, which is capable of producing a metal-coated product having the desired durability and aesthetic properties.